In one aspect, the invention relates to carbon black production. In another aspect, the invention relates to an apparatus for producing carbon black. In yet another aspect, the invention relates to changing out feed tubes in a furnace.
In the production of carbon black from a carbonaceous make oil, it is frequently desirable to change the nozzle through which the make oil is emitted into the reaction flow passage of the reactor. This is because the properties of the carbon black being produced can be varied by changing the nozzles. For example, in certain types of carbon black reactors, changing from a nozzle which emits a 20.degree. cone-shaped spray of feedstock to a nozzle which emits a 90.degree. cone spray dramatically changes the properties of the black produced. Also, nozzles sometimes become plugged or burn off in the reactor and must be removed for repair or replacement. Further, the pressure drop across a set of nozzles can be altered by changing out one of them.
In many plant production systems, it could take operators an hour or more to change over the feedstock nozzles. During this time period, if the reactor were equipped with multiple nozzles, the carbon black being produced would not be on specification and thus could not be easily sold. Were the furnace to be shut down to replace the feedstock nozzle, the subsequent cooling of downstream processing equipment could make possible the formation of acidic condensate which can damage downstream equipment such as the filter bags. Also, downstream processes which rely upon the heat of the reactor such as the wet pellet dryer would encounter operational difficulties.
In reactors where the oil nozzle is exposed, shutting down the oil flow to remove the nozzle allows excessive heating of the nozzle by the reactor combustion gases and sometimes the nozzle is thereby damaged. The oil nozzle can also be damaged when it is inserted into the reactor without flow of oil going through it due to overheating.
A process to avoid overheating of the oil nozzles during changeout operations would be very desirable. A process which provides for changing out the oil nozzles without shutting down the reactor would be very desirable. A process which provides for rapid changeout of oil nozzles with minimal production of altered product would also be very desirable.